So you have used SVM to mirror your disk, and one of the two drives fails. Aren’t you glad you mirrored them! You don’t have to do a restore from tape, but you are going have to replace the failed drive.

Many modern RAID arrays just require you to take out the bad drive and plug in the new one, while everything else is taken care of automatically. It’s not quite that easy on a Sun server, but it’s really just a few simple steps. I just had to do this, so I thought I would write down the procedure here.

Basically, the process boils down to the following steps:

Detach the failed meta devices from the failed drive

Delete the meta devices from the failed drive

Delete the meta databases from the failed drive

Unconfigure the failed drive

Remove and replace the failed drive

Configure the new drive

Copy the remaining drive’s partition table to the new drive

Re-create the meta databases on the new drive

Install the bootblocks on the new drive

Recreate the meta devices

Attach the meta devices

Let’s look at each step individually. In my case, c0t1d0 has failed, so, I detach all meta devices on that disk and then delete them:

At least in RHEL 4, the fdisk command does not support the creation of filesystems larger than 2TB. In order to get around it, you have to use the parted command. I found the basic info here, but this is the long and short of how to cut off a big ol’ slice of disk using parted:

Run parted

# /sbin/parted

It’s interactive, so the following commands are issued within the utility.

6)Finally, you don’t want to wait for that big filesystem to fsck from time to time, so make sure it does not get checked unless you run the command yourself:

# tune2fs -c0 -i0 /dev/sdb1

That should just about do it. Remember that only RHEL 4 and higher can support filesystems larger than 2TB. If I remember correctly RHEL 3 can go up to 2TB, RHEL4 can handle 8TB, and RHEL 5 can make a whopping 16TB chunk of disk. Have fun!

Getting Solaris 8 to light up a Qlogic QLA2310 Fibre Channel card using the SUNWqlc and SUNWqlcx drivers can be frustrating enough, but the headaches are only beginning if you want to connect it to a SAN and you don’t have all the right packages installed.

Last week, I installed the QLA2310 in a Sun Fire V210 running Solaris 8. I installed the latest versions of SUNWqlc, SUNWqlcx and SUNWsan. After doing a reboot -- -r, the system came up and attached the driver to the card. I zoned it in the fabric and logged into Navisphere, where the WWN showed up, but neither Power Path or the Navisphere host agent could communicate with the CLARiiON. I also could not see any of the LUNS I had presented.

I thought it was strange that the CLARiiON could see the host, but the host could not see the CLARiiON.

There it was… I didn’t have the complete SAN package installed. I hadn’t done this in a few years, so I had forgotten all the packages I had to add to get the Sun SAN package working correctly… There are many.

Happily, Sun has now packaged them in a nice “SAN_4.4.12_install_it.tar.Z”, which you can get from their website if you have a username. It installs everything for you in the right order.

The only thing left to do was another reboot -- -r and run cfgadm -c configure c3 to config the device. After this everything started working nicely.

When you install RHEL, the filesystems are labeled for you. Usually you won’t have to mess with it anymore, but on occasion, you may want to change them to more accurately represent the data that is stored on that partition. If, for instance, you used to have all of your database files on a partition labeled “/database”, but you have now moved them somewhere else, and you now wish to house your user account data there, it would make sense to change the label to something like “/users”.

Labels are, of course, arbitrary, so there is no technical need to do this, and you could, instead simply change the mount point in the fstab file, mounting the partition by device name rather than label, but it is usually cleaner to change the label. Here is how you do it:

First, let’s figure out what the partition is currently labeled as:

[root@calvin /]# /sbin/e2label /dev/hda4
/database
[root@calvin /]#

It’s current label is “/database”, and, since we have moved the database data somewhere else, we now want to store our user account data here, we need to change it to “/users”.

[root@calvin /]# /sbin/e2label /dev/hda4 /users
[root@calvin /]#

That’s all there is to it, now we check to make sure we have done what we think we have done.

[root@calvin /]# /sbin/e2label /dev/hda4
/users
[root@calvin /]#

Sure enough, it’s now labeled “/users” and the data on the disk remains intact. Now all we have to do is change the appropriate entry in the “/etc/fstab” file to represent the change.

Change this:

LABEL=/database /databases ext3 defaults 1 2

To this:

LABEL=/users /users ext3 defaults 1 2

And you’re all set to go. Make sure you have unmounted “/databases” before making the change.

Now, just run:[root@calvin /]# mount /users
[root@calvin /]#

And you’re all set to go. As always, change the values here to represent those in your environment.

If you manage a UNIX system with a large number of directories that vary in size, chances are that you’ve needed to figure out which ones are using up the most disk space. Of course if the directories are user accounts, the best way to do this is to enable quotas and use the “repquota” command. If you just have a bunch of directories, however, you can easily figure out which ones are largest by giving the correct arguments to “du” and “sort”. Here is how:

du -sk * | sort +0nr

This will display the size of all directories and sort them from largest to smallest. If you want to sort them from smallest to largest, simply remove the “r”.

du -sk * | sort +0n

If you have nested directories, you will need to incorporate foreach to recurse through and get all the directory names.

Kids… DO NOT TRY THIS AT HOME! If this is not done exactly right, you will render your system unbootable and corrupt your data. That being said, under some circumstances you can take some space from your swap partition and add it to an unused one without initializing your entire disk. This is particularly useful if you decide you want to use DiskSuite to mirror your system disk, but have not allocated the 100MB partition that is needed to hold the state databases. As always, BACK EVERYTHING UP FIRST. Better yet, make two backups and store them on two different systems. This is a risky procedure, and you don’t want to lose any data!

The first thing you need to do is figure out if your disk layout will allow for this procedure. Usually the swap partition is the second one on the disk, making it partition number 1 (Partition number 0 is root). If partition number 1 is swap on your system, and partition number 3 or 4 are unused, you are in good shape, and this should work. To figure this out, you should do something like this:

# format
Select the boot disk – usually disk 0Specify disk (enter its number): 0
format> partition
format> print
This will show you the current disk layout.

Here we see that partitions 3 and 4 are unused and directly after partition 1, so we can take some space from swap and assign it to one of these. Partition 2 is, of course the entire disk. I have not tried it, so I don’t know if you could assign non-sequential cylinders to a partition that is not directly after swap.

So to take some space from partition 1 and add it to partition 3, the first thing we have to do is disable swap, so the format utility will let us change it.

Comment out the following lines in your /etc/vfstab file and reboot the system.

#/dev/dsk/c1t0d0s1 - - swap - no -
#swap - /tmp tmpfs - yes -

This will bring the system up without swap enabled. You can now edit the disk label. Remember that our cylinders need to be sequential, so always work in cylinders when using the format utility.

Re-enter the format utility, select your system disk and view the partition table:

The first thing we need to do is take some cylinders away from partition 1. In this example, we are looking to make partition 3 roughly 100MB, so we need to take about 75 cylinders from partition 1 so that we can add it to partition 3. Parititon 1 ends at cylinder 9436, so we need to subtract 75 from that number. 9436 – 75 = 9361, so that is the new ending cylinder for partition 1. We then subtract the beginning cylinder (726) from that number to give us the new total number of cylinders for partition 1. 9361 – 726 = 8635, so this is the number we enter when format asks for the size of the partition. Like so:

Partition 1 ends at cylinder 9360, and partition 3 picks right up at cylinder 9361. Partition 3 ends at cylinder 9436, and partition 5 begins at cylinder 9437. Partition 4, of course, remains unused. Since none of the cylinders overlap, we can go ahead and write the disk label out. DO NOT DO THIS if you have any doubt at all about what you have just done. By writing out the disk label, you could corrupt the data on your formated filesystems if any cylinders overlap into them. The format utility is usually pretty smart about keeping you from making mistakes, but be very careful anyway! You don’t want to end up with scrambled eggs on a disk that has valuable data on it.

partition> label
This writes out the disk label, so you can now exit the format utility and re-enable swap in your /etc/vfstab file. Simply uncomment out the following two lines and reboot the system.

/dev/dsk/c1t0d0s1 - - swap - no -
swap - /tmp tmpfs - yes -

Reboot your system, and if all goes well, it will come up, and you will see that partition 3 will have a little over 100MB on it. Usually people want to do this so they can store the DiskSuite meta database on the newly created partition. If this is the case for you, you can now move on to mirroring the system disk.